Technology

Q&A: Internet Pioneer Looks Spaceward

September 24, 2007

Vint Cerf, an architect of the Net, talks about Google's Lunar X competition and the challenges of space communication

Vint Cerf may be best known for his role in the creation of the Internet, but his earliest professional years were spent in the space industry, during the heady years of the Apollo missions. While Cerf was in high school, his father worked at North American Aviation, a company that over the years created the X-15 rocket plane, the Saturn V rocket, and the Space Shuttle orbiter. During some summers in high school and college in the early 1960s, Cerf worked for two North American Aviation subsidiaries, including Rocketdyne, which created rocket engines. "I have a T-shirt that says, 'I am a rocket scientist,'" says Cerf, now chief Internet evangelist at Google GOOG.

During the intervening 33 years, Cerf went on to have a profound impact on the Internet. At the University of California at Los Angeles, he worked on the Advanced Research Projects Agency Network, or ARPANET, which revolutionized how information was sent over networks.

After graduating from UCLA with a PhD in computer science, Cerf teamed up with Bob Kahn to begin exploring how to connect several different networks, a project that culminated with the creation of the Internet. In 1976, he went to work for the Advanced Research Projects Agency, now known as DARPA, where he led the development of a series of instructions, or protocols, known as Transfer Control Protocol/Internet Protocol (TCP/IP), that guide how information travels over the Internet.

About a decade ago, Cerf turned his attention back to space—this time, to develop the protocols that will govern deep-space communications. Cerf recently spoke to BusinessWeek.com writer Rachael King about the challenges of space communication as well as Google's Lunar X competition, which encourages private lunar exploration. An edited excerpt of their conversation follows.

How did you get back to working in the space industry?

I had a long hiatus. In late 1997, I started thinking about how much earlier we had started working on the Internet, and only after, in this case, almost 30 years, the work was starting to mature and become significant. The thing that occurred to me is that we will eventually need much more elaborate communications than we have today for space-based applications.

The theory was that if we looked into the distant future—say, 100 to 200 years from now—we might see some significant numbers of robotic devices in the remotely controlled scientific stations, in orbit around the surface (of Mars), and maybe even people who might be manning scientific laboratories for some period of time, and they would need fairly elaborate communications, more along the lines of what we have come to use today on the Internet. Starting in 1998, my colleagues and I at the Jet Propulsion Lab began to lay out what this architecture would have to look like, and we've been at it for the last 10 years. We've gone through four iterations of the design, we've got implementations available.

What are the technical problems of communicating in deep space?

There are two big technical problems. The first one is plain speed-of-light delay. As you start going into interplanetary distances, you're talking tens of millions of miles or billions of miles, and at the speed of light those distances can sometimes take from many minutes to hours to cross. Another problem is celestial motion. Many of the planets and their satellites actually rotate on their axes. If you're behind the planet relative to the other party, you're not going to communicate very well.

What this adds up to is delay and disruption, which are inescapable properties of the space environment, either because of the distances involved or because of the celestial motions that are involved. The old TCP/IP wasn't going to work, so we had to invent new delay- and disruption-tolerant protocols to overcome the conditions we encountered.

What do you think of the Google Lunar X Prize and the commercialization of space?

I have been very impressed by the responsiveness of the technology community to these various prizes. The X Prize that won the $10 million, Burt Rutan for getting SpaceShipOne up into suborbital flight, is impressive. It's not an inexpensive process to get to the moon, so people are going to have to think very carefully and very cleverly about how to get sufficient thrust in order to break through the gravitational pull and get into orbit and then land on the surface in one piece. I'm a big fan of this kind of thing. It's acknowledging how important innovation is to us as a country.

Why is space important to you and other Internet veterans?

For a lot of people, there's a kind of background implicit belief that someday we have to get off the planet. We can't just sit here on our little blue marble and ignore everything. Maybe I've been watching too many Star Trek reruns, but I always believe that in the long run we are not and should not be a one-planet species. Although I'm also a practical engineer and I know that (making Mars inhabitable through a process known as) terraforming is not exactly child's play. Are we ever going to settle in some way on those other planets or their satellites? I really don't know.

Certainly over the next 100 years, it doesn't seem too likely that we would have significant settlements anywhere, but it depends an awful lot in part on economics. If, for example, it turned out there was a dramatic economic value to mining the moon, for example, you could be sure that some people would work really hard to figure out how on earth to do that.

Isn't one of the obstacles the high cost per pound to get off earth?

Yes. Right now, I think the cost is on the order of $10,000 per pound. If you got it down to $100 per pound or even $500 per pound, you'd be within reaching distance of some potentially interesting commercial opportunities. My guess is that tourism may be one of the early winners here. Building a hotel somewhere at the general altitude of the space station, you'd be weightless, you'd have a pretty amazing view. I know there are people thinking about the possibility of making hotels in space. Commercialization is what made the spread of the Internet possible, and so it may very well be that commercialization is going to make space travel—even if it is just near-earth space travel—possible, because it will drive the cost down.